In 5 1/2- to 6-quart saucepot, heat oil over medium heat. Add celery and leaves, onion, thyme, 1/2 teaspoon salt, and 1/4 teaspoon pepper, and cook 20 to 25 minutes or until celery is soft but not browned, stirring occasionally. Add wine and cook 2 minutes or until wine is mostly evaporated.

Add broth, potatoes, and water to saucepot; cover and heat to boiling over high heat. Reduce heat to low; cover and simmer 10 minutes or until potatoes are very tender.

In batches, ladle celery mixture into blender; cover, with center part of cover removed to allow steam to escape, and blend very well until pureed. Pour puree into large bowl. Repeat with remaining mixture.

Tips & Techniques

Do Ahead: Make soup up to 2 days before if refrigerating or up to 1 month before if freezing, and store in plastic containers with tight-fitting lids. Transport soup and garnish in cooler. Reheat refrigerated soup in a large covered saucepot over medium heat about 15 minutes or until hot, stirring occasionally. If starting with frozen soup, add 2 tablespoons water to saucepot before heating.